Ruthenium pi-arene complexes with certain aromatic compounds are known, see for instance R. M. Moriarty, et al., J. Organometal. Chem., vol. 350, p. 157-190 (1988). Such complexes in which a benzene ring contains one or two halogen atoms are known (see T. P. Gill et al., Organometallics, vol. 1, p. 485-488 (1982), and R. M. Moriarty, et al., ibid). The complexes which contain halogenated benzene rings are also known to undergo nucleophilic substitution reactions with phenoxides or thiophenoxides (R. M. Moriarty, et al., ibid).
However, to Applicant's knowledge, no pi-arene complex of ruthenium has been reported wherein the arene ring contains more than two halogen atoms. Furthermore, there are comments or experiments in the art where doubt has been expressed as to whether similar complexes with other metals (Cr, Fe) which contain 3 or more halogen atoms attached to the aromatic ring can be made, see G. Wilkinson, et al., Ed., Comprehensive Organometallic Chemistry, Vol. 3, Pergamon Press, Oxford, 1982, p. 1001; M. E. Wright, Organometallics, vol. 8, p. 407-411 (1989); V. Percec, et al., J. Polym. Sci. A, vol. 31, p. 923-932 (1993); and D. Astruc, Tet. (Tet. Reports No. 157), vol.-39, p. 4027-4095 (see especially p. 4038) (1983).